In recent years, a DaaS (Desktop as a Service) system in which a hypervisor is shared by a plurality of tenants has been attracting much attention among virtual machine creation systems. DaaS systems have advantages such as mitigation of loads on a client side and improvement of security because processing of a virtual desktop is executed on a server side.
On the other hand, the system has a shortcoming that even when a license for use in creating a virtual machine is not allowed on a hypervisor on which a virtual machine of other tenant operates, a virtual machine might be created by using the license on the hypervisor on which the virtual machine of other tenant operates.
Another problem is that even when a virtual machine is created by using the above-described license on a hypervisor on which no virtual machine of other tenant exists, a virtual machine of other tenant might be created thereafter.
Under these circumstances, recited as related art in Patent Literature 1, for example, is a technique having a mechanism of approving a software license in a virtual machine environment. The technique recited in Patent Literature 1 enables license check on a virtual machine basis.    Patent Literature 1: Japanese Patent Laying-Open No. 2006-018815.
Although the technique recited in Patent Literature 1 enables license check on a virtual machine basis, since the license check is executed for a virtual machine already created and not executed at the time of creation of a virtual machine, application of the technique recited in Patent Literature 1 fails to solve the above-described problems.